Method of making a multicomponent film

ABSTRACT

Described herein is a method and precursor composition for depositing a multicomponent film. In one embodiment, the method and composition described herein is used to deposit a germanium-containing film such as Germanium Tellurium, Antimony Germanium, and Germanium Antimony Tellurium (GST) films via an atomic layer deposition (ALD) and/or other germanium, tellurium and selenium based metal compounds for phase change memory and photovoltaic devices. In this or other embodiments, the Ge precursor used comprises trichlorogermane.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Patent Application No.61/810,919, filed on Apr. 11, 2013. The disclosure of Application No.61/810,919 is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

Disclosed herein is a method for depositing multicomponent films each ofwhich may be stoichiometric or non-stoichiometric such as, but notlimited to, Germanium Tellurium (GT), Antimony Germanium (SG), GermaniumAntimony Tellurium (GST), Germanium Oxide, Germanium Nitride. Precursorcompositions or mixtures thereof for depositing the multicomponent filmusing the method described herein are also contemplated.

Certain alloys such as but not limited to, GST (Germanium AntimonyTellurium alloy), and GeTe (Germanium Tellurium alloy) are used tofabricate electronic devices, including Phase Change Random AccessMemory (PCRAM). Phase-change materials exist in a crystalline state oran amorphous state according to temperature. A phase-change material hasa more ordered atomic arrangement and a lower electrical resistance in acrystalline state than in an amorphous state. A phase-change materialcan be reversibly transformed from the crystalline state to theamorphous state based on an operating temperature. Such characteristics,that is, reversible phase change and different resistances of differentstates, are applied to newly proposed electronic devices, a new type ofnonvolatile memory devices, phase-change random access memory (PCRAM)devices. The electrical resistance of a PCRAM may vary based on a state(e.g., crystalline, amorphous, etc.) of a phase-change material includedtherein.

Among various types of phase-change materials used for memory devices,the most commonly used are ternary chalcogenides of Group 14 and Group15 elements, such as Germanium Antimony Tellurium compounds of variouscompositions, including but not limited to Ge₂Sb₂Te₅, and commonlyabbreviated as GST. The solid phases of GST can rapidly change fromcrystalline state to amorphous state or vise versa upon heating andcooling cycles. The amorphous GST has relatively higher electricalresistance while the crystalline GST has relatively lower electricalresistance.

For the fabrication of phase change random access memory (PCRAM) with adesign requirement less than 20 nanometers (nm), the demand for goodprecursors for GeSbTe atomic layer deposition (ALD) has been increasingsince ALD is the most suitable deposition method for excellent stepcoverage, accurate thickness and film composition controls. The mostwidely investigated compositions of GST lie on the GeTe—Sb₂Te₃pseudo-binary tie line. However, ALD deposition of these compositions isdifficult because of the greater stability of Ge⁺⁴ precursors than Ge⁺²precursors and Ge⁺⁴ tends to form GeTe₂ instead of GeTe. Under thesecircumstances GeTe₂—Sb₂Te₃ composition films would be formed. Therefore,there is a need for precursors and related manufacturing methods orprocesses for forming GT and GST films which can produce films with highconformality and chemical composition uniformity, particularly using anALD deposition process.

BRIEF SUMMARY OF THE INVENTION

Described herein are methods, precursors and mixtures thereof fordepositing germanium-containing films. In this connection,trichlorogermane (HGeCl₃) can easily dissociate into HCl and GeCl₂ atrelatively low temperature. This property makes HGeCl₃ a suitableprecursor which can generate divalent germanium species in situ in thedeposition process. In one particular embodiment, HGeCl₃, when used in adeposition process with other precursors (Me₃Si)₂Te and (EtO)₃Sb, mayincrease the germanium composition in GST alloy, comparing with commonlyused Ge precursors such as (MeO)₄Ge. The use of HGeCl₃ as an germaniumprecursor allows one to solve the aforementioned problems of otherprevious germanium precursor and achieve the desired Ge₂Sb₂Te₅composition in certain embodiments.

One embodiment of the method for depositing a multicomponent film ontoat least a portion of a substrate comprises the steps of:

-   -   a) contacting the substrate with a Ge precursor comprising        HGeCl₃ to react with the substrate and provide a first coating        layer comprising Ge;    -   b) introducing a purge gas to remove any unreacted Ge precursor;    -   c) contacting the first coating layer comprising Ge with a Te        precursor, wherein at least a portion of the Te precursor reacts        with the Ge comprised therein to provide a second coating layer        comprising Ge and Te;    -   d) introducing a purge gas to remove any unreacted Te precursor;    -   e) contacting the second coating layer comprising Ge and Te with        a Sb precursor, wherein at least a portion of the Sb precursor        reacts with at least a portion of the Ge and Te comprised        therein to provide a third coating layer comprising Ge, Te, and        Sb; and    -   f) introducing a purge gas to remove any unreacted Sb precursor.

In certain embodiments, steps (a) through (f) are repeated a number oftimes until a desired thickness of coating layers is reached to providethe multicomponent film. In this or other embodiment, the steps may beperformed in the order of:

-   -   e→f→→a→b→c→d.

In a further embodiment, there is provided a process of depositing amulticomponent film onto at least a portion of a substrate comprisingthe steps of:

-   -   a. contacting the substrate with a Ge precursor comprising        HGeCl₃ to react with the substrate and provide a first coating        layer comprising Ge;    -   b. introducing a purge gas to remove any unreacted Ge precursor;    -   c. contacting the first coating layer comprising Ge with a Te        precursor, wherein at least a portion of the Te precursor reacts        with the Ge comprised therein to provide a second coating layer        comprising Ge and Te; and    -   d. introducing a purge gas to remove any unreacted Te precursor;        wherein steps (a) through (d) are repeated to form a number of        coating layers and provide the film.

In a further embodiment, there is provided a process of depositing agermanium-containing film onto at least a portion of a substratecomprising the steps of: providing the substrate within a reactor;introducing into the reactor a Ge precursor comprising HGeCl₃ underdeposition conditions sufficient to react with the substrate to providea germanium-containing film. In this or other embodiments, theintroducing further comprises an oxygen source or nitrogen source. Inthis or another embodiment, the germanium-containing film furthercomprises an oxygen source to provide a germanium oxide (GeO_(x;)x=1.2)film. Exemplary oxygen sources employed include, but are not limited to,oxygen (O₂), oxygen plasma, ozone (O₃), hydrogen peroxide, air, nitrousoxide, water plasma, and water. In a still further embodiment, thegermanium-containing film further comprises a nitrogen source to providea germanium nitride (GeN or Ge₃N₄) film. Exemplary nitrogen sourcesinclude but are not limited to ammonia, ammonia plasma,nitrogen/hydrogen plasma, and nitrogen plasma. In this or a stillfurther embodiment, the germanium-containing film comprises a puregermanium film via introducing hydrogen plasma. In this or a stillfurther embodiment, the germanium film further comprises nitridationusing nitrogen plasma or ammonia plasma or nitrogen/hydrogen plasma toconvert into a germanium nitride film.

In any of the preceding embodiments, it is understood that the steps ofthe methods described herein may be performed in a variety of orders,may be performed sequentially or concurrently (e.g., during at least aportion of another step), and any combination thereof. In certainembodiments, the steps described herein are performed sequentially toavoid formation of precipitates.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 provides the GeTe XRF compared to Ge pulse time (seconds) forthose films deposited on the SiO₂ and TiN substrates in Example 1.

FIG. 2 provides the GeTe XRF compared to Ge pulse time (seconds) forthose films deposited on the SiO₂ and TiN substrates in Example 2.

FIG. 3 provides the GeTe XRF compared to Ge pulse time (seconds) forthose films deposited on the SiO₂ and TiN substrates in Example 3.

FIG. 4 provides the GeTe XRF compared to Ge pulse time (seconds) forthose films deposited on the SiO₂ and TiN substrates in Example 4.

FIG. 5 provides the GeTe XRF compared to Ge pulse time (seconds) forthose films deposited on the SiO₂ and TiN substrates in Example 5.

FIG. 6 a provides the GeSbTe XRF using 50 ALD cycles consist of 1 GeTesequence and 1 SbTe sequence on a silicon oxide substrate in Example 6.

FIG. 6 b provides the GeSbTe XRF using 50 ALD cycles consist of 1 GeTesequence and 1 SbTe sequence on a titanium nitride substrate in Example6.

FIG. 7 a provides the GeSbTe XRF compared to cycle number for thosefilms deposited on the silicon oxide substrate in Example 7.

FIG. 7 b provides the GeSbTe XRF compared to cycle number for thosefilms deposited on a titanium nitride substrate in Example 7.

DETAILED DESCRIPTION OF THE INVENTION

To fabricate high density electronic devices such as phase change memory(PCRAM) or photovoltaic materials, Atomic Layer Deposition (ALD) is apreferred technology to deposit films, such as metal chalcogenide films,uniformly on small dimensional structures on a substrate surface. Incertain embodiments, the film comprises a metal chalcogenide film. Theterm “metal chalcogenide” as used herein refers to a film that containsone or more Group 16 ion (chalcogenide) and at least one electropositiveelement. Examples of chalcogenide materials include, but are not limitedto, sulfides, selenides, and tellurides. Conventional ALD technologyinvolves ALD reactors which typically operate under vacuum and atelevated temperature. It also requires that the precursors be volatileand thermally stable compounds in order to be delivered to the reactorchamber in the vapor phase. ALD is a type of chemical vapor depositionthat is used for highly controlled deposition of thin films. It is aself-limiting (e.g., the amount of film material deposited in eachreaction cycle is constant) and sequential (e.g., the precursor vaporsare brought onto the substrates alternately, one at a time, separated bypurging periods with inert gas) process. ALD is considered a depositionmethod with the greatest potential for producing very thin, conformalfilms with control of the thickness and composition of the filmspossible at the atomic level. Using ALD, film thickness depends only onthe number of reaction cycles, which makes the thickness controlaccurate and simple.

Described herein are methods and precursors for depositinggermanium-containing films are multi-component films such as withoutlimitation GeTe and GeTeSb films. Exemplary depositions temperatures forthe method described here include ranges having any one or more of thefollowing endpoints: 500, 400, 300, 200, 195, 190, 185, 180, 175, 170,165, 160, 155, 150, 145, 140, 135, 130, 125, 120, 115, 110, 105, 100,95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, and/or 20°C. Examples of particular temperature ranges include, but are notlimited to, from about 20 to about 200° C. or from about 50 to about100° C.

In certain embodiments, the germanium-containing films further comprisetellurium and are deposited using a tellurium precursor. Exemplarytellurium precursors can be selected from disilyltellurium,silylalkyltellurium, silylaminotellurium with the general structures of:

(R¹R²R³Si)₂Te (R¹R²R³Si)TeR⁴ (R¹R²R³Si)TeN(R⁴R⁵)

where R¹, R², R³, R⁴, and R⁵ are independently selected from hydrogen,an alkyl group having 1-10 carbons in linear, branched, or cyclic formswithout or with double bonds, or an C₃ to C₁₀ aryl groups.

In an ALD process, the tellurium precursors, alcohols, germanium andantimony precursors, such as (Me₂N)₄Ge and (Me₂N)₃Sb are introduced to adeposition chamber in any sequence in a cyclic manner by vapor draw ordirect liquid injection (DLI). The deposition temperature is preferablybetween 25° to 500° C.

One embodiment of the method for depositing a multicomponent film ontoat least a portion of a substrate comprises the steps of:

-   -   a) contacting the substrate with a Ge precursor comprising        HGeCl₃ to react with the substrate and provide a first coating        layer comprising Ge;    -   b) introducing a purge gas to remove any unreacted Ge precursor;    -   c) contacting the first coating layer comprising Ge with a Te        precursor wherein at least a portion of the Te precursor reacts        with the Ge comprised therein to provide a second coating layer        comprising Ge and Te;    -   d) introducing a purge gas to remove any unreacted Te precursor;    -   e) contacting the second coating layer comprising Ge and Te with        a Sb precursor, wherein at least a portion of the Sb precursor        reacts with at least a portion of the Ge and Te comprised        therein to provide a third coating layer comprising Ge, Te, and        Sb; and    -   f) introducing a purge gas to remove any unreacted Sb precursor.

In certain embodiments, steps (a) through (f) are repeated a number oftimes until a desired thickness of coating layers is reached to providethe multicomponent film. In this or other embodiment, the steps may beperformed in the order of:

-   -   e→f→→a→b→c→d.

Another embodiment of the method for depositing a multicomponent filmonto at least a portion of a substrate comprises the steps:

-   -   a) Introducing HGeCl₃ to react with substrate to cover the        substrate surface with Ge—Cl fragments    -   b) Purging with inert gas    -   c) Introducing a Te precursor to provide a Te layer and    -   d) Purging with inert gas to remove any reaction by-products.        The ALD cycle is repeated a certain number of times until the        desired film thickness is achieved. In the above embodiment, the        next ALD cycle starts with Steps a) to d) and the steps are        repeated continues until the desired thickness of film is        obtained. In yet another embodiment of the method for depositing        a multicomponent film onto at least a portion of a substrate        comprises the steps:    -   a) introducing a Sb precursor to form a Sb layer comprising        aminoantimony on the surface of the substrate    -   b) purging with inert gas to remove any reaction by-products    -   c) introducing a Te precursors to react with aminoantimony layer        to form Sb—Te with a Te layer comprising silyl groups    -   d) purging with inert gas to remove any reaction by-products    -   e) introducing a Ge precursor comprising HGeCl₃ to react with        remaining silyl groups on tellurium layer to form Te—Ge bonds        with a Ge layer comprising Ge—Cl groups    -   f) purging with inert gas    -   g) introducing a Te precursors to react with aminoantimony layer        to form Sb—Te with a Te layer comprising silyl groups and    -   h) purging with inert gas to remove any reaction by-products.

The ALD cycle is repeated a certain number of times until the desiredfilm thickness is achieved. In the above embodiment, the next ALD cyclestarts with Step a through Step h which is then repeated continues untilthe desired thickness of film is obtained. In this or other embodiment,the steps may be performed in the order of:

-   -   e→f→g→h→a→b→c→d.        In certain embodiments, the order of Steps a to h can be        alternated to achieve required GST film such as ratio of Ge vs        Sb or Ge vs Te.

Exemplary silyltellurium compounds used in the process described hereinhave the following formulae:

(R¹R²R³Si)₂Te; (R¹R²R³Si)TeR⁴; and (R¹R²R³Si)TeN(R⁴R⁵)

where R¹, R², R³, R⁴ and R⁵ are each individually a hydrogen atom, analkyl groups with 1 to 10 carbons in a linear, branched, or cyclic form,or aromatic groups with 4 to 10 carbons.

Exemplary aminogermanes, aminoantimony, and antimony alkoxides in theprocess described herein have the following formulae:

(R¹R²N)₄Ge (R¹R²N)₃Sb (R¹O)₃Sb

where R¹ and R² are each individually alkyl groups with 1 to 10 carbonsin linear, branched, or cyclic form.

In the formulae above and throughout the description, the term “aryl”denotes an aromatic cyclic or an aromatic heterocyclic group having from4 to 10 carbon atoms, from 4 to 10, from 5 to 10 carbon atoms, or from 6to 10 carbon atoms. Exemplary aryl groups include, but are not limitedto, pyrrolyl, phenyl, benzyl, chlorobenzyl, tolyl, and oxylyl.

In one embodiment, the multicomponent film is deposited using an ALDmethod. The method described herein can be used to provide a thin filmin a deposition apparatus. The deposition apparatus consists of thefollowing parts.

-   -   A reactor where a substrate is placed, precursor vapors react        and form films. The reactor walls and substrate holder can be        heated at the same or different temperatures;    -   One or more liquid or solid precursor containers. The containers        may also be heated if needed;    -   One or more valves that may switch on or off the vapor flows to        the reactor from the precursor containers. A mass flow        controller (MFC) unit is used to control when and how much        valves 3 and 4 switch;    -   A vacuum pump that pumps out air or precursor vapors from the        reactor. A valve switches on/off the pumping line;    -   A vacuum gauge that measures the pressure level within the        reactor; and    -   An inert or purge gas (Ar or N₂) that switches on or off via a        valve.

In a typical ALD process, the reactor is filled with inert gas (e.g., Aror N₂) through an inlet and then pumped out using a vacuum pump 8 to avacuum level below 20 mTorr. The reactor is then filled with inlet gasagain and the reactor wall and substrate holder are heated to atemperature between 25° C. to 500° C. at which the deposition is set tobegin. The Ge precursor is delivered from precursor container that isheated to a certain temperature range. The temperature remains constantduring the deposition. The precursor is delivered from a precursorcontainer that is heated to a temperature between 25° C. to 500° C. Thetemperature also remains a constant during the deposition. The number ofthe cycles is preset according to the film thickness that ispredetermined. The GST films are formed by repeating the processes forGe and Sb, respectively. The processes for the growth of Ge and Sb aresimilar to that for Te.

Existing ALD methods of making GST films from alkoxygermanes,alkoxyantimony, and silyltellurium generate GST films with compositionof (GeTe₂)_(x)(Sb₂Te₃)_(y), with a typical formula of Ge₂Sb₂Te, wheregermanium is tetravalent. Industry preferred GST material is Ge₂Sb₂Te₅in the composition group of (GeTe)_(x)(Sb₂Te₃)_(y), where germanium isdivalent. In order to increase germanium content in the film to achieveGe₂Sb₂Te₅, divalent germanium precursors have to be used. Most ofdivalent germanium compounds are either unstable or less volatile in adeposition process such as ALD. The method described herein provides,without being bound by theory, in-situ generation of divalent germaniumwhich is used as intermediate to deposit divalent germanium on filmsurface. In certain embodiments, the trichlorogermane precursor is usedto deposit germanium-containing films, such as without limitation,binary films GeTe as well as ternary films such as Ge₂Sb₂Te₅. Describedherein is a method for depositing a multi-component film usingtrichlorogermane as precursor for ALD and CVD deposition of germaniumcontaining thin films, such as GST films for PRAM applications.Trichlorogermane generates dichlorogermylene inside the depositionchamber. Dichlorogermylene reacts with disilyltellurium to form GeTe,which further combine with Sb₂Te₃ to form phase change materialGe₂Sb₂Te₅ for phase change memory allocations.

In one embodiment of the method described herein, the germaniumprecursor HGeCl₃ was used for GeTe film deposition having a 1:1composition by an ALD deposition process. Using the tellurium precursorsuch as (Si Me₃)₂Te as a Te precursor, GeTe could be formed as followingequations (1) and (2).

HGeCl₃→GeCl₂+HCl  (1)

GeCl₂+(SiMe₃)₂Te→GeTe+2Me₃SiCl  (2)

The byproduct or equation (2), Me₃SiCl is volatile, a pure GeTe film canbe deposited.

In another embodiment of the method described herein, the germaniumprecursor HGeCl₃ was used for GeSe film deposition having 1:1composition by an ALD deposition process. Using the silylseleniumprecursor such as (Me₃Si)₂Se as a Se precursor, GeSe could be formed asfollowing equations (3) and (4).

HGeCl₃→GeCl₂+HCl  (3)

GeCl₂+(SiMe₃)₂Se→GeSe+2Me₃SiCl  (4)

The byproduct or equation (4), Me₃SiCl is volatile, a pure SeTe film canbe deposited.

Examples of tellurium precursors or Te precursors may comprisedisilyltellurium, silylalkyltellurium, or compounds having the generalstructures of: (R¹R²R³Si)₂Te and (R¹R²R³Si)R⁴Te. Examples of Selenium orSe precursors may comprise disilylselenium, silylalkylselenium, orcompounds having the general structures of: (R¹R²R³Si)₂Se or(R¹R²R³Si)R⁴Se. In the foregoing formulas, substituents R¹, R², R³, andR⁴ are each independently: hydrogen; linear, branched, or unsaturatedC₁₋₁₀ alkyl groups; and C₄₋₁₀ cyclic alkyl groups, or C₄₋₁₂ aromaticgroups. The term “alkyl” as used herein is selected from the groupconsisting of: linear, branched, or unsaturated C₁₋₁₀ alkyl groups; andC₄₋₁₀ cyclic alkyl groups, preferably from 1 to 6 carbon atoms, morepreferably from 1 to 3 carbon atoms, alternately from 3 to 5 carbonatoms, further alternately from 4 to 6 carbons atoms, or variations ofthe foregoing ranges. Exemplary alkyl groups include, but are notlimited to, methyl (Me), ethyl (Et), n-propyl, isopropyl, n-butyl,isobutyl, sec-butyl, tert-butyl, tert-amyl, n-pentyl, n-hexyl,cyclopentyl, and cyclohexyl. The term “alkyl” applies also to alkylmoieties contained in other groups such as haloalkyl, alkylaryl, orarylalkyl. In certain embodiments, some of the groups discussed hereinmay be substituted with one or more other elements such as, for example,a halogen atom or other heteroatoms such as O, N, Si, or S.

Examples for the silyltellurium precursor include, but are not limitedto, bis(trimethylsilyl)tellurium, bis(dimethylsilyl)tellurium,bis(triethylsilyl)tellurium, bis(diethylsilyl)tellurium,bis(phenyldimethylsilyl)tellurium, bis(t-butyldimethylsilyl)tellurium,dimethylsilylmethyltellurium, dimethylsilylphenyltellurium,dimethylsilyl-n-butyltellurium, dimethylsilyl-t-butyltellurium,trimethylsilylmethyltellurium, trimethylsilylphenyltellurium,trimethylsilyl-n-butyltellurium, and trimethylsilyl-t-butyltellurium.

Examples for the silylselenium precursor include, but are not limitedto, bis(trimethylsilyl)selenium, bis(dimethylsilyl)selenium,bis(triethylsilyl)selenium, bis(diethylsilyl)selenium,bis(phenyldimethylsilyl)selenium, bis(t-butyldimethylsilyl)selenium,dimethylsilylmethylselenium.

The deposited films that can be made in accordance with the methodsdescribed herein are selected from the group selected from GermaniumTellurium (GT), Antimony Germanium (SG), Germanium Antimony Tellurium(GST), Germanium Oxide, and Germanium Nitride.

In one particular embodiment, the GST film is deposited usingtrichlorogermane. Trichlorogermane has an unique property. It is inequilibrium with germanium dichloride and HCl at room temperature (seeequation (3)).

HGeCl₃

GeCl₂+HCl  Equation 3

Germanium dichloride and HCl form loosely bonded complex. This complexcan be distilled without decomposition (boiling point 75° C.) underatmospheric pressure. On the other hand, this complex can be pull apartby high vacuum at low temperature and generate pure germaniumdichloride, which is a solid.

Described herein is a method for using trichlorogermane as germaniumprecursor for GST films. Trichlorogermane is delivered into ALD reactorchamber in vapor phase. The molecule is decomposed into germaniumdichloride and HCl by low pressure to allow germanium dichloride toanchor on the substrate surface, and consequently reacts withdisilyltellurium in ALD cycles to form GT films such as GeTe films, orGST films with disilyltellurium and antimony alkoxides such as antimonyethoxide or aminoantimony such as tris(dimethylamino)antimony asantimony (Sb) precursors.

GeCl₂+(Me₃Si)₂Te→GeTe+Me₃SiCl

Sb(OEt)₃+(Me₃Si)₂Te→Sb₂Te₃+Me₃SiOEt

Sb(NMe₂)₃+(Me₃Si)₂Te→Sb₂Te₃+Me₃SiNMe₂

GeTe+Sb₂Te₃→(GeTe)_(x)(Sb₂Te₃)_(y)

Germanium dichloride also reacts with trisilylantimony to form Ge₃Sb₂films

GeCl₂+(Me₃SO₃Sb→Ge₃Sb₂+Me₃SiCl

Examples for the aminoantimony include, but are not limited to,tris(dimethylamino)antimony, tris(diethylamino)antimony,tris(di-iso-propylamino)antimony, tris(di-n-propylamino)antimony,tris(di-sec-butylamino)antimony, and tris(di-tert-butylamino)antimony.

Examples for the antimony alkoxides include, but are not limited to,antimony ethoxide ((EtO)₃Sb), antimony methoxide ((MeO)₃Sb), antimonyiso-propoxide ((^(i)PrO)₃Sb), antimony n-propoxide ((^(n)PrO)₃Sb),antimony sec-butoxide ((^(s)BuO)₃Sb), antimony tert-butoxide((^(t)BuO)₃Sb).

Examples for the trisilylantimony precursors include, but are notlimited to, tris(trimethylsilyl)antimony, tris(dimethylsilyl)antimony,tris(triethylsilyl)antimony, tris(diethylsilyl)antimony,tris(phenyldimethylsilyl)antimony, tris(t-butyldimethylsilyl)antimony.

The aforementioned examples are merely illustrative, and do not limitthis disclosure in any way. While the method and precursor compositionshave been described in detail and with reference to specific examplesand the embodiments thereof, it will be apparent to one skilled in theart that various changes and modifications can be made therein withoutdeparting from the spirit and scope thereof.

EXAMPLES Example 1 Deposition of GeTe Film

Deposition was performed in an ALD reactor manufactured by Quros reactorwith a shower head type PEALD chamber with a load lock, which can handleone 4 inch wafer. The phase transition properties of samples and filmswere characterized by Energy Dispersive X-ray Analysis.

A GeTe film was obtained with in the following manner. The HGeCl₃canister temperature was around 1° C., and (Me₃Si)₂Te canistertemperature was at 40° C. A typical wafer temperature is 70° C., typicalAr gas flow rate is 500 sccm, and the reactor pressure is controlled at3 Torr. The film was deposited in the following manner after a wafer wasloaded on a heated susceptor in the reactor and Ar gas was flowing intothe reactor for a few minutes.

-   -   a) Ge precursor pulse step; HGeCl₃ vapor is introduced into the        reactor for typically 0.1 sec using a vapor draw method. The        vapor draw method used herein means that the vapor of a        precursor comes from a canister without any help of a carrier        gas, and so only outlet valve of the canister opens at a pulse        step.    -   b) Ar (Ge) purge step; Ar gas flows into the reactor for seconds        to remove any unreacted Ge species and reaction byproducts.    -   c) Te precursor pulse step; (Me₃Si)₂Te vapor is introduced into        the reactor for a few seconds by Ar carrier gas (50 sccm)        flowing through the Te canister.    -   d) Ar (Te) purge step; Ar gas flows into the reactor for seconds        to remove any unreacted Te species, and reaction byproducts.        Steps a) to d) were repeated 100 times to obtain a required film        thickness.

Using the above procedure, both silicon oxide and titanium nitride assubstrate, trichlorogermane as Ge precursor, andbis(trimethylsilyl)tellurium as Te precursor, GeTe films were depositedin the sequence in each cycle were tested: (1) various seconds of Gepulse; (2) 30 seconds Ar purge; (3) 4 seconds Te pulse; and (4) 40seconds Ar purge. XRF indicated the Ge/Te atomic ratio is 1:1. FIG. 1provides the GeTe XRF compared to Ge pulse time (seconds) for thosefilms deposited on the SiO₂ and TiN substrates. Same result can beobtained when the Te precursor pulse step can be applied first insteadof Ge precursor pulse step.

Example 2 ALD Satuation Curve: Te Precursor Pulse Time Vs. GeTeDeposition Rate

Using a procedure similar to that described in Example 1 and siliconoxide and titanium nitride as substrates, trichlorogermane as Geprecursor, and bis(trimethylsilyl)tellurium as Te precursor, GeTe filmswere deposited via ALD. 100 ALD cycles with the following sequence ineach cycle were tested: (1) 0.1 second Ge pulse; (2) 20 seconds Arpurge; (3) various seconds of Te pulse; and (4) 20 seconds Ar purge. XRFindicated the Ge/Te atomic ration of 1:1. FIG. 2 provides the GeTe XRFcompared to Te pulse time (seconds) for those films deposited on theSiO₂ and TiN substrates.

Example 3 ALD Satuation Curve: Ge Precursor Pulse Time Vs. GeSbDeposition Rate

Using a procedure similar to that described in Example 1 and siliconoxide and titanium nitride as substrates, trichlorogermane as Geprecursor, and tris(trimethylsilyl)antimony as Sb precursor rather thana Te precursor, GS films were deposited via ALD. 100 ALD cycles with thefollowing sequence in each cycle were tested: (1) various seconds of Geprecursor pulse; (2) 30 seconds Ar purge; (3) 3 seconds Sb precursorpulse; and (4) 30 seconds Ar purge. XRF indicated the Ge/Sb atomic ratioof 1:1. FIG. 3 provides the GeSb XRF compared to Sb precursor pulse time(seconds) for those films deposited on the SiO₂ and TiN substrates.

Example 4 ALD Satuation Curve: Sb Precursor Pulse Time Vs. GeSbDeposition Rate

Using a procedure similar to that described in Example 1 and siliconoxide and titanium nitride as substrates, trichlorogermane as Geprecursor, and tris(trimethylsilyl)antimony as Sb precursor rather thana Te precursor, GeSb films were deposited via ALD. 100 ALD cycles withthe following sequence in each cycle were tested: (1) 0.1 second Geprecursor pulse; (2) 20 seconds Ar purge; (3) various seconds of Sbprecursor pulse; and (4) 20 seconds Ar purge. XRF indicated the Ge/Sbatomic ratio of 1:1. FIG. 4 provides the GeSb XRF compared to Sb pulsetime (seconds) for those films deposited on the SiO₂ and TiN substrates.

Example 5 GeTe Deposition Rate Vs. Substrate Temperature

Using above procedure, both silicon oxide and titanium nitride assubstrate, trichlorogermane as Ge precursor, andbis(trimethylsilyl)tellurium as Te precursor. 100 ALD cycles with thefollowing sequence in each cycle were tested: (1) 0.1 second Geprecursor pulse; (2) 30 seconds Ar purge; (3) 4 seconds Te precursorpulse; and (4) 40 seconds Ar purge. The resulting data show that theGeTe deposition rates decreased as the temperatures increased in thetemperature range of 50 toll 0° C. FIG. 5 provides the GeTe XRF comparedto substrate temperature (degrees celsius) for those films deposited onthe SiO₂ and TiN substrates.

The above examples show that GeTe films exhibited 1:1 compositions underthe ALD deposition conditions described above. Saturation conditionswith these precursors, and GeTe deposition rate at 70° C. was 1.16A/cycle. Deposition rate decreased gradually with increase of substratetemperatures. XPS results showed very low Cl and C impurities in theGeTe film.

Example 6 Deposition for GeSbTe Ternary Film

Ge—Sb—Te ternary films were deposited in a shower-head-type ALD reactorwith a 6-inch-wafer scale (CN-1, Atomic-premium) at temperatures rangingfrom 50° C. to 120° C. using HGeCl₃ as the Ge precursor, Sb(OEt)₃ as theSb precursor, and Te(SiMe₃)₂ as the Te precursor. The HGeCl₃ canistertemperature was around 1° C., Sb(OEt)₃ canister temperature was at 40°C., and Te(SiMe₃)₂ canister temperature was at 40° C. The filmcomposition was determined by XRF.

Using a procedure similar to that described in Example 1, except thatthe antimony precursor is introduced first, and silicon oxide andtitanium nitride as substrates, bis(trimethylsilyl)tellurium as Teprecursor and antimony ethoxide as Sb precursor rather than a Geprecursor, SbTe films were deposited via ALD. Combining SbTe depositionprocedure and GeTe deposition procedure (from Example 1) can depositGeSbTe films by repeating a) to d) steps in procedure using Sb/Te orGe/Te precursors (called GeTe sequence and SbTe sequence, respectively).FIGS. 6 a and 6 b provides the GeSbTe XRF using 50 ALD cycles consistingof 1 GeTe sequence and 1 SbTe sequence on silicon oxide and titaniumnitride substrates, respectively. The total layer density was 4.31 ugcm⁻² on the SiO₂ substrate and 4.84 ug cm⁻² on the TiN substrate. Thenumber of each sequence in one ALD cycle can be modified to change thecomposition of films.

Example 7 GeSbTe Ternary Film Growth Vs Cycle

Using a procedure similar to that described in Example 6 and siliconoxide and titanium nitride as substrates, trichlorogermane as Geprecursor, antimony ethoxide as Sb precursor andbis(trimethylsilyl)tellurium as Te precursor, GeSbTe ternary film weredeposited. Various number of cycles was tested with the followingsequence in each cycle: (a) 3 seconds of Sb precursor pulse; (b) 15seconds Ar purge; (c) 1 second of Te precursor pulse; (d) 15 seconds ofAr purge; (e) 5 seconds of Ge precursor pulse; (f) 15 seconds of Arpurge; (g) 1 second of Te precursor pulse; and (h) 15 seconds of Arpurge. FIGS. 7 a and 7 b provides the GeSbTe XRF compared to cyclenumber for those films deposited on the silicon oxide and titaniumnitride substrates, respectively. By the procedure, Ge:Sb:Te ratio of15:35:50 film was deposited.

1. A method of depositing a multicomponent film on at least a portion ofa substrate comprising the steps of: a) contacting the substrate with aGe precursor comprising HGeCl₃ to react with the substrate and provide afirst coating layer comprising Ge; b) introducing a purge gas to removeany unreacted Ge precursor; c) contacting the first coating layercomprising Ge with a Te precursor comprising the Te precursor, whereinat least a portion of the Te precursor reacts with the Ge comprisedtherein to provide a second coating layer comprising Ge and Te; d)introducing a purge gas to remove any unreacted Te precursor; e)contacting the second coating layer comprising Ge and Te with a Sbprecursor, wherein at least a portion of the Sb precursor reacts with atleast a portion of the Ge and Te comprised therein to provide a thirdcoating layer comprising Ge, Te, and Sb; f) introducing a purge gas toremove any unreacted Sb precursor; wherein steps (a) through (f) arerepeated to form a number of coating layers and provide the film.
 2. Themethod of claim 1 wherein the Te precursor comprises a silyltelluriumselected from the group consisting of disilyltellurium having a generalformula: (R¹R²R³Si)₂Te; alkylsilyltellurium having a general formula:(R¹R²R³Si)TeR⁴; and mixtures thereof wherein R¹, R², R³, and R⁴ are eachindependently selected from the group consisting of: hydrogen; linear,branched, or unsaturated C₁₋₁₀ alkyl groups; C₄₋₁₀ cyclic alkyl groups;and C₄₋₁₂ aromatic groups.
 3. The method of claim 2 wherein the Teprecursor comprises a disilyltellurium having the following formula:(R₃Si)₂Te.
 4. The method of claim 3 wherein the Te precursor comprisesbis(trimethylsilyl)tellurium.
 5. The method of claim 1 wherein the Sbprecursor comprises a compound selected from the group consisting of acompound having the general structure (RO)₃Sb; a compound having thegeneral structures (R¹R²R³Si)₂Sb; and a compound having the generalstructure (R¹R²R³Si)R⁴Sb wherein substituents R, R¹, R², R³, and R⁴ areeach independently: hydrogen; linear, branched, or unsaturated C₁₋₁₀alkyl groups; and C₄₋₁₀ cyclic alkyl groups, and C₄₋₁₂ aromatic groups.6. The method of claim 1 wherein the Sb precursor comprises a compoundhaving the following formula: MX_(n), wherein M is Sb; X is anucleophilic group selected from the group consisting of OR (alkoxy), F(fluorine), Cl (chlorine), Br (bromine), NR₂ (amino), CN (cyano), OCN(cyanate), SCN (thiocyanate), diketonate, carboxylic groups and mixturesthereof; and n equals the oxidation state of the metal.
 7. The method ofclaim 5 wherein the Sb precursor comprises tris(trimethylsilyl)antimony.8. A method of depositing a multicomponent film on at least a portion ofa substrate comprising the steps of: a) contacting the substrate with aGe precursor comprising HGeCl₃ to react with the substrate and provide afirst coating layer comprising Ge; b) introducing a purge gas to removeany unreacted Ge precursor; c) contacting the first coating layercomprising Ge with a Te precursor wherein at least a portion of the Teprecursor reacts with the Ge comprised therein to provide a secondcoating layer comprising Ge and Te; and d) introducing a purge gas toremove any unreacted Te precursor; wherein steps a) through d) arerepeated to form a number of coating layers and provide the film.
 9. Themethod of claim 8 further comprising: a) contacting the second coatinglayer comprising Ge and Te with a Sb precursor, wherein at least aportion of the Sb precursor reacts with at least a portion of the Ge andTe comprised therein to provide a third coating layer comprising Ge, Te,and Sb; b) introducing a purge gas to remove any unreacted Sb precursor;wherein steps a) through b) are repeated to form a number of coatinglayers to provide the GST film.
 10. A method for depositing agermanium-containing film onto at least a portion of a substratecomprising the steps of: providing the substrate within a reactor; andintroducing into the reactor a Ge precursor comprising HGeCl₃ underdeposition conditions sufficient to react with the substrate and providethe film.
 11. The method of claim 10 wherein the method furthercomprises introducing an oxygen source into the reactor to react withthe Ge precursor and provide a germanium oxide film.
 12. The method ofclaim 11 wherein the oxygen sources comprises at least one selected fromthe group consisting of oxygen (O₂), oxygen plasma, ozone (O₃), hydrogenperoxide, air, nitrous oxide, water plasma, and water.
 13. The method ofclaim 10 wherein the method further comprises introducing an nitrogensource into the reactor to react with the Ge precursor and provide agermanium nitride film.
 14. The method of claim 11 wherein the nitrogensource comprises at least one selected from the group consisting ofammonia, ammonia plasma, nitrogen/hydrogen plasma, and nitrogen plasma.15. The method of claim 10 wherein the method further comprisesintroducing hydrogen plasma into the reactor to react with the Geprecursor and provide a germanium film.
 16. A method of depositing amulticomponent film on at least a portion of a substrate comprising thesteps of: a) introducing a Sb precursor to form a Sb layer comprisingaminoantimony on the surface of the substrate. b) purging with inert gasto remove any reaction by-products. c) introducing a Te precursor toreact with aminoantimony layer to form Sb—Te with a Te layer comprisingsilyl groups. d) purging with inert gas to remove any reactionby-products e) introducing a Ge precursor comprising HGeCl₃ to reactwith remaining silyl groups on tellurium layer to form Te—Ge bonds witha Ge layer comprising Ge—Cl groups f) purging with inert gas. g)introducing a Te precursor to react with aminoantimony layer to formSb—Te with a Te layer comprising silyl groups. h) purging with inert gasto remove any reaction by-products wherein steps a) through h) arerepeated to form a number of coating layers and provide GST film. 17.The method of claim 16 wherein the Te precursor comprises asilyltellurium selected from the group consisting of disilyltelluriumhaving a general formula: (R¹R²R³Si)₂Te; alkylsilyltellurium having ageneral formula: (R¹R²R³Si)TeR⁴; and mixtures thereof wherein R¹, R²,R³, and R⁴ are each independently selected from the group consisting of:hydrogen; linear, branched, or unsaturated C₁₋₁₀ alkyl groups; C₄₋₁₀cyclic alkyl groups; and C₄₋₁₂ aromatic groups.
 18. The method of claim17 wherein the Te precursor comprises a disilyltellurium having thefollowing formula: (R₃Si)₂Te.
 19. The method of claim 18 wherein the Teprecursor comprises bis(trimethylsilyl)tellurium.
 20. The method ofclaim 16 wherein the Sb precursor comprises a compound selected from thegroup consisting of a compound having the general structure (RO)₃Sb; acompound having the general structures (R¹R²R³Si)₃Sb; and a compoundhaving the general structure (R¹R²R³Si)₂R⁴Sb wherein substituents R, R¹,R², R³, and R⁴ are each independently: hydrogen; linear, branched, orunsaturated C₁₋₁₀ alkyl groups; and C₄₋₁₀ cyclic alkyl groups, and C₄₋₁₂aromatic groups.